Moldable cone bellows



Dec. 18, 1956 N. GREENE 2,774,518

MOLDABLE CONE BELLOWS Filed June 2, 1953 2 Sheets-Sheet l INVENTOR.MOAZMA/V (fkEEA/ Dec. 18, 1956 N. GREENE 2,774,518

MOLDABLE CONE BELLOWS Filed June 2, 1953 2 Sheets-Sheet 2 i .lZ.

INVEN TOR. ,vazmw GZEEA/E United States PatentO MOLDABLE CONE BELLOWSNorman Greene, New York, N. Y.

Application June 2, 1953, Serial No. 359,124

16 Claims. (Cl. 222209) This invention relates to bellows for squeezecontainers, and more particularly to a conical (or pyramidal) bellowsuseable as part of a container.

The primary object of the present invention is to generally improveflexible bellows, and containers using the same. A more particularobject is to provide a bellows which is so contoured and constructedthat it may be molded between the halves of a simple two-part mold whichopens in a direction axially of the bellows. Still another object is toprovide a bellows which, although readily deformable is characterized bya strong restoring force which dependably brings the same back toinitial position. With these objects in view I have devised acompressible bellows shaped to form a series of concentric stepsconverging upwardly, with each of said steps having what may, forconvenience, be termed a generally upright wall and a generallyhorizontal wall, the said walls preferably being disposed within angularlimits later defined. p M I A further object of the invention is todevise a bellows which may be used with containers intended to carry anddispense food products, drug products, and cosmetics. Plastic moldingmaterials which have come into wide use in recent years for this purposeare polyethylene and polyisobutylene and mixtures of the two. Theseplastics are flexible, but experience negligible, if any, compression orstretch. In this respect they are quite different from a flexiblematerial such as rubber, for example. This characteristic may occasiondifiiculty when using a stepped bellows of the type so far describedbecause when the bellows is depressed the steps tend to turn inward,resulting in a reduction in the circumferential length of the steps.

A further object of the present invention is to overcome thisdifiiculty, which I do by providing the bellows with radial grooves.These grooves ascend with the steps, and are preferably deeper than theindividual steps. When the bellows is depressed the sides of the groovescome toin accordance with a further feature and object of the presentinvention, the lower ends of the grooves terminate in a generallyupright wall, the arrangement being such as to permit the lower ends ofthe grooves to yield outwardly when the bellows is compressed.

To accomplish the foregoing general objects, and other i "ice Fig. 3 isa side elevation of the bellows;

Figs. 4 and 5 are fragmentary sections through the bellows and areexplanatory of the operation of the same;

Fig. 6 is a fragmentary plan view of the bellows in depressed orsqueezed condition;

Fig. 7 is a vertical section through a modified form of bellows havingan integral threaded ring;

Fig. 8 is a partially sectioned elevation of a modified container inwhich the bellows is secured to the container with a snap fit;

Fig. 9 is a partially sectioned elevation of a modified container inwhich the side wall of the container is molded integrally with thebellows;

Fig. 10 is a plan view of a modified bellows in which the convergingsteps are generally pyramidal rather than conical;

Fig. 11 illustrates the range and preferred angle for the generallyvertical walls of the steps;

Fig. 12 illustrates the range and preferred angle for the generallyhorizontal walls of the steps;

Fig. 13 shows overstressing of the bellows; and

Fig. 14 shows a modification of the bellows.

Referring to the drawing, and more particularly to Figs. 1, 2 and 3, thebellows there illustrated has a series of concentric steps 12, 14 and 16which converge upwardly. Each of'the steps has what may, forconvenience, be called a generally upright wall 18, and a generallyhorizontal wall 20.

Referring to Fig. 11, which corresponds to the lower left end of thebellows section in Fig. 1, it may be explained that the generallyupright wall may be disposed at an angle in a range of from toconsidered in clockwise direction as shown on the drawing. The preferredangle is very close to vertical, and is slightly greater than 90, say92, in order to facilitate the molding operation by providing taper ordraft which helps release the bellows from the mold.

The generally horizontal wall is disposed at an angle of from 0 to 45below horizontal, as shown by the range in Fig. 12 of the drawing, andit is preferably at an angle of from 10 to 20 below horizontal, thisbeing the shaded area in Fig. 12.

The bellows may be made of metal, rubber, or many of the known plasticssuch as cellulose acetate, but when used with dispensing containersintended to carry food products, drug products, and cosmetics, thebellows is preferably molded out of polyethylene, polyisobutylene, ormixtures of the two. This plastic is flexible, but is virtuallynon-compressible and non-stretchable. When the bellows is compressed orsqueezed downward, as shown by the change from Fig. 4 to Fig. 5 of thedrawing, the steps tend to fold or roll inward, as shown by the changein position of the parts 12, 14 and 16. This is accompanied by adecrease in diameter and circumferential dimension for each step. Inorder to accommodate this change without excessively stressing thematerial, I provide the bellows with radial grooves, shown at 22, 24,26, 28 in Fig. 2. Thesegrooves ascend with the steps, and they arepreferably deeper than the individual steps, as will be seen frominspection of Figs. 3 and 4. The sides of the groove may come together,that is, the grooves may narrow, as will be seen by comparison of thegrooves 22 and 28 in Figs..2 and 6. Thus the grooves readily accommodatethe reduction in peripheral length of the steps when the bellows ispressed.

By referring toFig. 3 it will be seen that the lower end of groove 26terminates in the generally upright wall 18. This is done in order tomore readily accommodate the outwardmovernent of the grooye portionitself. Thus by comparing Figs. 4 and 5 it will be seen that when thebellows is pressed downward the groove 28 moves from the angularposition shown in Fig. 4 to the substantially horizontal position shownin Fig. 5, and this results in an outward movement which is accommodatedby an outward bulging or ballooning of the wall 18. The net etfect ofthis construction is that the bellows is readily pushed downward withoutexcessively stressing the material and yet is returned to initialposition with a good restoring force.

Reverting now to Fig. 1, the bellows there shown is used to close thetop of an open-topped jar or container 30. This may be a rigid glasscontainer of conventional type. It is provided with a threaded neckportion 32. The bellows has a flange or horizontal peripheral portion 34of suitable diameter to rest on top of the neck portion 32 of the jar.The bellows is secured in position by means of a threaded ring 36, whichmay be made of metal. This ring is threaded at 38 to mate with thethreaded part 32 of the jar, and it has a flange portion 40 whichoverlies the flange 34 of the bellows. No additional gasket is neededbecause the material of the bellows is somewhat yieldable and, itself,forms a satisfactory gasket.

The central portion of the bellows is preferably solid and acts as araised knob or stud 42 which facilitates depression of the bellows. Itis provided with a blind vertical hole 44 which receives the upper endof a pump tube 46, the lower end of which tube preferably reaches thebottom of the container. The stud portion 42 further has a blind radialhole 48 which communicates with the vertical hole 44 and which receivesa discharge tube or spout 50. It will be evident that by depressing thebellows some of the content of the jar 30 is delivered through the spout50. The stud 42 is preferably provided with a vent hole 52. The lowerportion 54 of the vent hole may be of increased diameter in order tofacilitate molding the same, but at least the upper part of the venthole is of minute bore or capillary dimension. The main purpose of thevent hole is to take care of expansion of air above the liquid contentof the jar resulting from temperature change, typically on removing thecontainer from a refrigerator to the table.

It will be noted that the entire bellows structure, including the stud4-2, may be molded between the halves of a simple two-part mold,excepting only the radial hole 48 for the spout 59. A retractable coreis preferably provided in the mold for this purpose, although it ispossible under more limited production conditions to form one or more ofthe holes in other ways, as by drilling in a suitable fixture or jig.The stud portion 42 is preferably made solid or largely solid, as shown,despite the consumption of a small additional amount of the plasticmolding material, because the preferred plastics are not susceptible ofbeing joined by adhesive or solvent action, and it is therefore simpleand economical to secure the tubes 46 and 50 by means of a force fit,the tubes being forced into the mating holes 44 and 48 formed in therelatively solid stud portion at the center of the bellows. It will beunderstood that the pump tube 46 and spout 50 have been omitted in theremaiinng figures of the drawing in order to simplify the same.

Fig. 7 shows a modified bellows top intended for use on a jar like thatshown at 30 in Fig. 1. This modification differs in that the bellows,instead of terminating in the flat horizontal flange portion 69 (Fig.7), is additionally formed with an integral cylindrical portion 62 whichis internally threaded at 64 to mate with the threaded portion 32(Fig. 1) of the jar. It will be understood that the threads 64 arerelatively rounded and that the proportioning of the parts is such thatthe threads may be stripped from the ejector half of the die after thedie has been opened. This procedure is already known in the molding ofplastic materials, and is mentioned only to make it clear that thebellows is adapted for molding directly between two mold parts whichseparate in a direc tion axially of the bellows, despite the presence ofthe thread 64.

The form of the invention shown in Fig. 8 is generally similar to thosealready described, except that the bellows top, generally designated 70,is secured to the jar or container 72 with a snap fit. Specifically, theupper end or neck portion of the container is provided with a groove 74.The cylindrical part 76 of the bellows is provided with an inwardlydirected lip or undercut 78 dimensioned to mate with the groove 74. Theparts are suitably dimensioned and shaped to permit the same to be puttogether with the desired snap fit.

Fig. 9 shows a modified form of the invention in which the side wall 80of the container is made of the same plastic and is molded integrallywith the bellows 82. Thus the complete container is formed in a singlemolding operation, except for the bottom 84. The bottom may itself bemolded and may be secured to the side wall 84 in any desired fashion as,for example, by fusing or welding the parts together by application ofheat, or more simplyby means of a snap engagement, for which purpose theside wall 80 is thinned or necked slightly at the point 86.

As so far described the bellows has been assumed 'to be circular orconical, but other shapes may be employed, and Fig. 10 shows a modifiedbellows which is square or pyramidal. Thus referring to Fig. 10 it willbe seen that the walls of the steps on each side are straight, as shownat 90, 92, 94, 96. The grooves or channels 98 are preferably disposeddiagonally of the resulting square, and are mutually at right angles, asis clearly shown in the drawing. The central portion 100 is a solid studor knob as previously described, and may be provided similarly with avent hole and with intersecting blind holes, one vertical to receive apump tube, and the other approximately horizontal to receive a dischargetube or spout.

The bellows terminates in a fiat area or flange 102, and this has beenshown circular in Fig. 10 for use at the top of a cylindrical container,but it will be understood that the flange 102 might equally well besquare for use on top of a square container. It will also be understoodthat the bellows of Fig. 10 may be provided with an internally threadedcylindrical portion as shown at 62, 64 in Fig. 7, or with a side wallportion arranged for a snap fit as indicated at 76, 78 in Fig. 8, orwith an integral side wall as indicated at 80 in Fig. 9. Theconstructions of Figs. 8 and 9 are applicable to a square outline asWell as a circular outline. In that connection it will be understoodthat the bellows may be made in other shapes than square as, forexample, rectangular, triangular, elliptical, etc.

Under some circumstances the bellows may be subjected to excessivestress. It may be pushed down an amount beyond that indicated in Fig. 5,thus bringing the parts to a position somewhat like that shown in Fig.13. The same effect may be produced at one side only of the bellows bypushing it 'sidewardly instead of straight down. When the bellows isstressed excessively the bottom of the groove is subjected to across-tension or splitting force which tends to split the groovelengthwise along the bottom.

In bellows designed for purposes in which the bellows may be repeatedlysubjected to overstress of this nature I prefer to make the groove witha cross-section resembling a W instead of a U. This is illustrated inthe modification shown in Fig. 14 of the drawing. This view is the sameas that shown in Fig. 3 already described, but in the present case thegroove, generally designated 126, is reversely formed or upwardly convexalong its bottom cen ter line, as shown at 128. The contour of thesection may be called W but is preferably rounded, rather than sharpangled. It will be evident that with this corrugated or W cross-section,the bottom region of the groove is well adapted to expand sidewardly,and thus to accommodate the spreading tendency or cross-tension to whichit is subjected when the bellows is compressed for a substan tialdistance.

In Fig. 14 the dotted line 130 represents the bottom of the next step132. It has been shown in order to 1l1ustrate a detail which is notessential, but which is preferred in practice, namely, the fact that theheight of the raised center portion 128 preferably should not exceed theheight of the line 130. This is merely for convenience in fabricatingthe die in which the bellows is molded, because it makes it possible tocut the steps in a lathe, without interference by the mold parts whichcorrespond to the raised center part 128 of the channel.

Before closing this description it may be pointed out that thecompressible bellows may be employed for purposes other than the pumpaction illustrated in Fig. 1. It may, for example, be used with a tophaving a spray hole, or with a conical nozzle such as is used on oilcans, or with a dispensing cup arrangement such as that shown in U. S.Patent No. 2,599,446.

The bellows works in the following manner. As pressure is applied thereis a convergence of the steps of the bellows. In order to allow thediameter of each step to be reduced, they are divided by the ascendinggrooves, which fold in a direction at right angles to the steps, andthus permit the reduction by bending, rather than by compressing orstretching the material. Thus the minimum width of this ascending grooveis determined as that which allows adequate space for the maximumconvergence which occurs when the bellows is totally compressed. Thenumber of these ascending grooves may range from one upward, it being amatter of design, affected by the type of material used, and theflexibility and rebound properties desired.

The ascending grooves themselves may act as ribs antagonistic to thecompression of the bellows. This is overcome by ending the groove in aflexible area, namely, at a point well above the junction of thevertical portion of the bottom step and the flange, thus allowing thiswall to balloon out at the point where the groove joins it. There may beless or more than the four grooves shown.

The ability to injection mold or stamp a bellows that allows this greatdegree of displacement olfers many advantages, due to its ease ofmanufacture and low cost, in a variety of fields and uses, where it maybe employed as a dispensing mechanism for drugs, chemicals, foods andcosmetics in the packaging field, or mechanical uses where a taperedbellows may be applied.

In general, a pumping action at the top has the advantage of making thebellows useable with a convenventional glass jar, but even when theentire container is made of plastic it has an advantage compared to asqueezing action at the sides, for the latter tends to break the sealbetween the sides and the base.

The wall thickness of the bellows should be such as to allow ampleflexibility, yet with suflicient rigidity to obtain a spring-back to theresting position. This wall thickness would vary with the flexibility ofthe particular plastic or molding material used.

If desired the ascending grooves of the bellows may be given a W insteadof a U cross-section, thereby affording spreading at the bottom of thegrooves, as well as contraction at the top of the grooves. This takescare of any difficulty which might otherwise arise from cross-tension orsplitting at the bottom of the grooves.

It is believed that the construction and operation, as well as theadvantages of my improved bellows, will be apparent from the foregoingdetailed description. It will also be apparent that while I have shownand described my invention in several preferred forms, changes may bemade in the structures shown without departing from the scope of theinvention, as sought to be defined in the following claims. In theclaims the reference to a generally upright wall and a generallyhorizontal wall is to be considered in a relative rather than anabsolute sense, it being obvious that the bellows may be mounted in avertical instead of a horizontal position, to be squeezed horizontallyinstead of vertically, or in any other desired po- 6 sition which may beconvenient for the particular use intended.

I claim:

1.- A vertically compressible bellows comprising a single body ofmaterial shaped to form a series of concentric steps convergingupwardly, each step having a generally upright wall and a generallyhorizontal wall, said bellows having radial grooves ascending with thesteps, and said grooves being deeper than the individual steps, saidgrooves narrowing to accommodate the reduction in peripheral length ofthe steps when the bellows is compressed, the lower end of each of saidgrooves terminating in an upright wall to yield outwardly when thebellows is compressed.

2. A moldable vertically compressible bellows comprising a single bodyof material shaped to form a series of concentric steps convergingupwardly, each step having a generally upright wall and a generallyhorizontal wall, said generally upright wall being disposed at an angleof from to with respect to the horizontal, said generally horizontalwall being disposed at an angle of from 0 to 45 below horizontal, andsaid bellows having radial grooves ascending with the steps, saidgrooves narrowing to accommodate the reduction in peripheral length ofthe steps when the bellows is compressed.

3. A moldable vertically compressible bellows comprising a single bodyof material shaped to form a series of concentric steps convergingupwardly, each step having a generally upright wall and a generallyhorizontal wall, said generally upright wall being disposed at an angleof from 90 to 135 with respect to the horizontal, said generallyhorizontal wall being disposed at an angle of from 0 to 45 belowhorizontal, and said bellows having radial grooves ascending with thesteps, said grooves narrowing to accommodate the reduction in peripherallength of the steps when the bellows is compressed, the material beingselected from the group consisting of polyethylene and polyisobutyleneand mixtures of the two.

4. A moldable vertically compressible bellows comprising a single bodyof material shaped to form a series of concentric steps convergingupwardly, each step having a generally upright wall and a generallyhorizontal wall, said generally upright wall being disposed at an angleclose to but slightly greater than 90 with respect to the horizontal,said generally horizontal wall being disposed at an angle of from 10 to20 below horizontal, said bellows having radial grooves ascending withthe steps, and said grooves being deeper than the individual steps, saidgrooves narrowing to accommodate the reduction in peripheral length ofthe steps when the bellows is compressed, and the lower end of each ofsaid grooves terminating in an upright wall to yield outwardly when thebellows is compressed. I

5. A vertically compressible bellows comprising a single body ofmaterial shaped to form a series of concentric steps convergingupwardly, each step having a generally upright wall and a generallyhorizontal wall, and said bellows having radial grooves ascending withthe steps, said grooves narrowing to accommodate the reduction incircumferential length of the steps when the bellows is compressed.

6. A bellows as defined in claim 5, in which the central portion is araised knob or stud having a blind vertical hole for receiving the upperend of a pump tube, and having a blind radial hole communicating withsaid vertical hole for receiving the inner end of a discharge spout.

7. A bellows as defined in claim 5, in which the concentric steps arecircular, and in which there are four radial grooves disposed mutuallyat right angles to one another when viewed in plan.

8. A bellows as defined in claim 5, in which the concentric steps formthe four sides of a square, and in which there are four grooves disposeddiagonally of the square and mutually at right angles to one another.

9. A bellows as defined in claim 5, in which the periphcry of thebellows is provided with a generally cylindrical fiange having aninternal thread dimensioned to mate with the threaded neck of a jar orcontainer on which the bellows is to be used.

10. A bellows as defined in claim 5, in which the peripheral portion ofthe bellows is provided with a cylindrical flange having an undercutdimensioned to be received with a snap fit over the upper edge of a jaror container with which the bellows is to be used.

11. A bellows as defined in claim 5, in which the peripher'y of thebellows projects downward for a substantial distance to form thecylindrical wall of a container, whereby the container and bellows areformed integrally except for the bottom of the container.

12. A bellows as defined in claim 5, in which the radial grooves have across-section somewhat resembling a W, in order to accommodate expansionat the bottom of the groove.

13.-A moldable vertically compressible bellows compris'ing a single bodyof material shaped to form a series of concentric steps convergingupwardly, each step having a generally upright wall and a generallyhorizontal wall, said generally upright Wall being disposed at an angleclose to but slightly greater than 90 with respect to the horizontal,said generally horizontal wall being disposed at an angle of from 10 to20 below horizontal, said bellows having radial grooves ascending withthe steps, and said grooves being deeper than the individual steps, saidgrooves narrowing to accommodate the reduction in peripheral length ofthe steps when the bellows is compressed, and the lower end of each ofsaid grooves termimating in an upright wall to yield outwardly when thebellows is compressed, the material being selected from the groupconsisting of polyethylene and polyisobutylene and mixtures of the two.

14. A bellows as defined in claim 13, in which the radial grooves have across-section somewhat resembling a W, in order to accommodate expansionat the bottom of the groove.

15. A bellows as defined in claim 13, in which the central portion is araised knob or stud having a blind vertical hole for receiving the upperend of a pump tube, and having a blind radial hole communicating withsaid vertical hole for receiving the inner end of a discharge spout, andhaving a minute vent hole.

16. A bellows as defined in claim 13, in which the concentric steps arecircular, and in which there are four radial grooves disposed mutuallyat right angles to one another when viewed in plan, and in which theradial grooves have a cross-section somewhat resembling a W, in order toaccommodate expansion at the bottom of the groove.

References Cited in the file of this patent UNITED STATES PATENTS1,293,864 Morton Feb. 11, 1919 1,975,265 Fulenwider Oct. 2, 19342,275,666 Wilson Mar. 10, 1942 2,314,263 Witt Mar. 16-, 1943 2,680,477Schira June 8, 1954 2,686,006 I-Iasselquist Aug. 10, 1954

